Conventional passenger aircraft, for example Airbus aircraft such as the Airbus A340 aircraft, include an arrangement of waste water tanks, waste water drain lines, and various connections, couplings and other accessories for installing the tanks and the drain lines in the below-deck space of the aircraft fuselage, and connecting the tanks to the toilets, on-board galleys and the like, for receiving and storing the waste water generated by the toilets, galleys, and the like. The installation and connection of these tanks and drain lines is quite complicated and time consuming. Furthermore, since the available installation space is quite limited and tight, and it is necessary to install up to three waste water tanks of relatively large volume in the available tight space, it is already quite difficult simply to transport and position the tanks at the intended installation location.
Furthermore, the complete waste water tank system comprises a rather great number and variety of different connection parts, mounting parts, heatable pipe sections and pipe joints, and various other unwieldy installation components, mounting brackets, securing devices and the like, of relatively complex configuration. A separate waste water drain line or pipe is connected respectively to each one of the waste water tanks, and these drain lines are connected to a pipe junction. From there, a main drain line conveys the waste water drained out of the waste water tanks to its intended location, for example to be emptied out of the aircraft through a drain mast connected to the main drain line. The drain lines and drain connections arranged below the tanks are rather costly, complex in configuration with numerous branching locations and joints, and are thus quite subject to disruption or damage leading to waste water leakage, and generally causing problems in the installation and maintenance of the overall system in the rather tight available space.
FIG. 1 of the present application schematically illustrates an example of a conventional arrangement of maximally three liquid storage containers or tanks 1 arranged in the below-deck space of a conventional aircraft such as an Airbus aircraft. Each one of the tanks 1 is a substantially cylindrical shaped tank with a complete circular cross-section (not shown in the vertical section of FIG. 1), and has a rather large volume capacity for storing liquid 5, such as accumulated waste water. The plural tanks 1 are arranged adjacent one another at the corners of a triangle clustered symmetrically around a vertical or upright axis (not shown).
These tanks 1 are connected to the various toilets, galleys, and the like in the aircraft by suitable water inlet or supply lines 3 such as waste water pipes that are connected to respective inlet openings 31 provided in the tops of the respective liquid tanks 1. These water lines or pipes 3 run below the aircraft deck floor that separates the passenger cabin and the like from the below-deck space inside the fuselage. The liquid 5, for example the waste water arising in the on-board galleys and the toilets, is transported by suction through a respective one of the water inlet lines 3 to a respective individual liquid tank 1, which is de-pressurized to a certain vacuum or negative pressure, for example by any conventional suction or vacuum source (not shown).
Furthermore, a respective drain or outlet line 4 is connected individually to a drain or outlet opening 41 provided at the center of the bottom of each individual tank 1. Thus, three individual drain or outlet lines 4 are connected to the three individual tanks 1, and all of these drain lines 4 must be arranged to have the required slope for achieving a proper liquid drainage. These plural drain lines 4 extend and are connected to a pipe branch junction 42 that leads to a further drain line 43 and that is arranged below the floor level of the several tanks 1 generally centered among the tanks along the vertical upright axis extending centrally between the tanks. All of these drain lines must be heated by suitable heating elements, such as electrical heating conductors, so as to prevent a freezing of the waste water or an icing of the drain lines during flight operation of the aircraft.
As generally discussed above, the conventional water storage tank arrangement suffers many problems and disadvantages, including a rather high complexity, a rather difficult and time-consuming installation, a great variety of different pipes, connectors, and other components, and a great difficulty of arranging the drain pipes and the necessary pipe junction in the small available space below the tanks. Furthermore, in the event of a leak or the like, it is extremely difficult to exchange a defective tank, pipe component, pipe coupling, or the like, which greatly increases the costs of on-going maintenance and repair. Furthermore, it is essentially impossible to expand the total liquid storage capacity of the installed system, because it is not economically practical to install any additional tank or tanks in the small available space if requested by the aircraft customer.